In a variety of applications and industries, it is desirable to have a coating that presents a slippery, non-fouling surface. In such applications, mechanical and optical properties of the coating are also often important.
Previous solutions involve super hydrophobic coatings, hydrophilic coatings, and oil bleeding and smooth low surface energy coatings. However, these solutions typically lack of transparency, and/or insufficient lubricity.
Thus, there is a need to improve coatings presenting a slippery surface, which can be transparent, self-lubricating, and/or non-fouling or anti-fouling.
Further, there is a more particular need regarding growth and accumulation of marine organisms which leads to severe economic and environmental penalties. Anti-fouling paints with biocides are the most abundantly used method to combat biofouling. Anti-fouling paints release organic or inorganic biocides which are toxic to marine organisms. Although majority of state of the art antifouling paints assure no significant toxicity, some ingredients (tri-butyl tin, TBT) used in the past have been shown direct threat to marine life and humans. Silicone based fouling release marine coatings are a non-toxic approach, where fouling organisms adhere weakly and can be easily released due to hydrodynamic shear or pressure. These coatings depend on low surface energy of silicones and fluoropolymers. Given the vast diversity in adhesion preferences of marine organisms, traditional fouling release coatings based on low surface energy coatings discussed in prior arts U.S. Pat. Nos. 2,986,474 A, 3,702,778 A, US20090221752 A1, U.S. Pat. Nos. 6,899,955 B2, and 8,574,719 B2 are deficient in providing broad spectrum resistance to biological fouling in the marine environment. As a result, the fouling release compositions described in prior art have shorter life cycle (decreased performance over time) compared to biocidal antifouling paints. Having a slippery self-lubricating surface based on a thin liquid overlayer has been shown to provide less accumulation of fouling organisms compared to commercial references without a slippery surface based on a liquid overlayer.